Libusb.org Sound Cards & Media Devices Driver

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From Simple English Wikipedia, the free encyclopedia
Creative Sound BlasterLive!, a PCI sound card

A sound card (audio card) is the part of the computer hardware that controls the input and output of the sound signals. A sound card is what is known as an expansion card. This means that the card can be added to the motherboard.

Nowadays, most of the audio cards are integrated with the motherboard. That means they are built into a mainboard and can not be removed. In other words, it is not an expansion card anymore. They only offer line-in, speaker, and microphone connections. For most users this is enough. When thinking of computer architecture, the integrated circuit sound cards occupy less space and thus became very popular and practical, especially for laptop computers. For more features like MIDI ports for connection of musical instruments and low latency requirements (so that the sound does not come distorted under heavy system usage) sound cards as expansion cards can be used. Modern expansion sound cards use the PCIcomputer bus standard. Earlier sound cards used the ISA computer bus, which was half-duplex, so the sound cards could not record and play simultaneously.

If libusb-0.1 does all that you need, I'd heavily recommend it. The libusb-0.1 API will be supported for some time to come with libusb-1.0 plus libusb01compat. Or you could even just stick to the old libusb-0.1 for several years to come with no real problems. This will take you to the 'Recording' Tab of your PC's Sound Management Mixer (Windows 7='Sound'; Win XP='Recording Control') where you can find and/or enable the line in on your input soundcard. Connect a 50 ohm antenna to your Rig's antenna connector; Connect your Rig's USB connector to one of your rig's USB ports; Apply power to your rig.

Sound Blaster sound cards for PC gaming and entertainment audio. A wide range of Z-series, Recon3D series, Sound BlasterAxx series & X-Fi series are available. Includes Internal sound cards & External (USB) sound cards for the best audio and gaming exper.

Input and output signals[changechange source]

What we hear in speakers is an analog (current, voltage or electric charge) output of the signal. For example, stored on a hard disk digital code is transferred under a control of some application (for example Winamp) to the sound card. Up in there, a special chip, called digital-to-analog converter, changes the binary code into the analog sound. Afterwards, signal is sent to a jack (in modern audio cards it has the green color) where the speakers are connected. The result is a nice waveform of our favorite digital medium, e.g. an mp3.

A typical sound input device is a microphone, connected to the red/pink jack socket. The sound wave is digitized and then it may be stored as a file using data compressionalgorithms which make the file smaller. Of course all of this is done under the control of some software.

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From The RadioReference Wiki

Raspberry Pi Broadcastify Feed Appliance

These instructions show you how to purchase and setup a completely self contained Raspberry Pi to broadcast a live audio feed to Broadcastify.com

These instructions have been verified and tested as working on a Raspberry Pi 2 Model B Project Board - 1GB RAM - 900 MHz Quad-Core CPU. Also installed and working on a Raspberry Pi 3 Model B (1 GB RAM - 1.2GHz 64 bit Quad-Core CPU - built in 802.11n wireless).

If you want to skip the build process, you can download our preconfigured Raspberry Pi image here Raspberry_Pi_Broadcastify_Image

  • 5Two Choices of Software to Broadcast
  • 7Troubleshooting

Purchase Equipment

Raspberry Pi 2 Model B Project Board

-or-Raspberry Pi 3 Model B+ Project Board

-or-Raspberry Pi 3 Model B+ Kit, includes power supply, case, heat sinks, in-line power switch (recommended)

Power Supply with in-line switch for Raspberry Pi

Memory Card for Raspberry Pi

Case for Raspberry Pi (optional)

Inexpensive USB sound card ($9)

1/8 inch audio cable to connect scanner to USB sound card

Install Raspbian OS

All testing and configuration was done using Raspbian

  • Follow the instructions here to install the OS on the memory card you purchased:

Install pre-reqs and update raspberry pi to latest version

Configure the Sound Card

  • Plug your scanner's headphone jack into the mic jack on the USB sound card dongle
  • Start alsamixer
  • press F6, choose the 'USB Headphone Set' entry
  • press your tab key to select the 'Capture' device volume control
  • use your 'up arrow' key to adjust the level to it's lowest level possible (6)
  • press escape to exist alsamixer
  • run the following command to save the volume settings

Two Choices of Software to Broadcast

We recommend the darkice install and configuration method

Method 1: Darkice Install and Configuration (Recommended)

  • download the precompiled version of darkice

Libusb.org Sound Cards & Media Devices Drivers

  • uncompress the files
  • move the files to the proper places and make sure they are executable
  • Edit the /etc/darkice1.cfg file to match your settings, including the sound card you are using, your feed server, mount, password, and description, then exit and save the file
  • Enable the feed to start broadcasting at boot
  • Start your feed

Method 2: Ezstream Install and Configuration

Create the following configuration file at /etc/ezstream_bcfy.xml and replace with your mount, password, and stream name. If you plan on having multiple streams make sure and create a separate named configuration file (i.e.'/etc/ezstream_bcfy2.xml) for each stream and reference accordingly in your command script below.

  • Run this command to start the sound card broadcast

Note: very little volume will be needed from your scanner - adjust the levels as appropriate for a good sounding feed.


Optional Scripts

  • Discussion: Script to alert feed owner to high number of listeners Thread


Troubleshooting

Clicking sound in the audio stream

If your stream has a clicking sound when there is no audio, you may be able to eliminate it by turning off Auto Gain Control.

  • Start alsamixer
  • Press F6 and select your audio device
  • Press Tab to select 'Auto Gain Control'
  • Press the 'm' key to toggle it off
  • Press Escape key to exit alsamixer
  • Save your settings with the following command

Darkice not working or not starting on boot

Libusb.org Sound Cards & Media Devices Driver

The procedure above for starting the darkice service on boot does not seem to work on Raspbian Buster Lite (version: July 2019). This is due to newer versions of Raspbian implementing service management via systemd. It's possible to get it working using Raspbian Stretch and a crontab.

Instead of following the instructions to install the latest version of Raspbian, install the Stretch version:

See Full List On Mxlinux.org

  • Download the image here: 2019-04-08-raspbian-stretch-lite.zip, or use the non-lite version if you want the GUI.
  • Use Balena Etcher or similar to flash it onto your SD card
  • Enable SSH (optional) by adding a blank file named 'ssh' to the SD card
  • Use raspi-config to set your timezone and expand the filesystem if necessary
  • reboot and follow the steps above, starting with 'apt-get update', and stopping after editing your /etc/darkice1.cfg file


Set up 'screen' and use it to run darkice in a detached screen, where it will keep running even if you close your terminal.

Sound
  • Install screen
  • run darkice in a screen, specifying your config file

At this point, you should be able to confirm that darkice is running, and streaming your audio.


Now, set up a cron tab to automatically restart things after every reboot.

  • Edit or start your cron file.

If it tells you there's no cron file, let it create one. Choose option 2 for the nano editor.

  • add the following line to the bottom of your cron file:

This runs after every reboot. It waits 30 seconds (to allow your network and other requirements to finish loading), and then starts a screen with darkice, using your config file.

Reboot and check that darkice is running:

The two ps commands should each return a line showing that screen and darkice are running. Your audio should now start streaming about 30 seconds after each reboot.

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